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Corneal ulcers commonly occur in horses due to their curious and flighty nature. Ulceration of
the most superficial part of the eye should be examined by a veterinarian promptly as they may develop into a more serious problem. Common signs of a corneal ulcers or other ocular issues are excessive tearing (epiphora), squinting (blepharospasm), swollen eyelids (blepharitis), small (miotic) pupil, conjunctivitis, and sometimes the ulcer itself or a cloudy area on the cornea is visible.

"Glass" had a history of habronema, a parasite also known as summer sores. In this case, flies had deposited the parasite when they landed in her eyes and transmitted the Habronema causing severe conjunctivitis. This irritation caused her to rub her eyes which caused a superficial corneal ulcer. Treatment for Habronema and a full ophthalmic exam was performed.

Notice the slightly more downward angle of the right eyelashes compared to the left. Sometimes this is the only sign of a corneal ulcer.

The next step is a complete ophthalmic exam. Glass had a visible defect on the cornea, no inflammation within the anterior chamber of the eye (no flare), and no miosis. Fluorescein staining of the eye revealed the following:
Fluorescein stain will only adhere to damaged cornea, as seen here with the green stained area in the eye. This is a superficial corneal ulcer.

Treatment of a superficial corneal ulcer can be very difficult in horses because many become aversive to medicating their eye directly (especially Glass!). Without treatment, the ulcer is very unlikely to heal and will progress and be a constant source of pain.

For Glass, we placed a subpalpebral lavage system (SPL) to make treating ocular issues like hers much easier. This device allows for a person to stand by the mane of the horse and administer liquid medications through small tubing. A small footplate anchors the tubing in place beneath the eyelid. The tubing is then sutured in place to allow for long term treatment of the eye. Treatment is administered up to every 2 hours through the SPL.

Glass's ulcer began to heal, but the new outer layer of the cornea was not adhered. Debridement with a sterile q-tip was performed to remove the loose epithelium which makes the ulcer appear larger, but actually promotes appropriate healing. Within a few days after debridement, her ulcer was much improved.

Picture before and after debridement with Q-tip

Glass's ulcer began to contract rapidly, as is normal with a healthy cornea. Corneal ulcer contracting and stain uptake decreasing shown here.

After no stain uptake was seen, Glass's treatment was continued for 3-5 days to make sure the ulcer was healed. Only a small scar was left after full treatment.

If you think your horse may have a corneal ulcer, don’t delay, have it treated immediately to avoid serious complications!